Engine control switches are used in air compressors, auxiliary generators, water pumps, marine engines, and various other devices. The switches are set to "make or break" an electrical contact at a predetermined pressure or vacuum within the switch. Typically, to test the pressure or vacuum at which these switches "make or break" contact, the switches must be installed in automobiles or other mechanically operated equipment. That causes problems because it is difficult and time consuming to install control switches in engines, compressors, pumps, automobiles, etc. Therefore, if a defective or improperly set engine control switch is installed in an automobile or other engine driven unit, the switch may not be determined to be defective or improperly set until after the switch is already installed. Thus, the switch must be removed, adjusted or replaced, and then reinstalled. This may need to be repeated several times before the switch is properly set or replaced to correct pressure or vacuum setting problems. This consumes valuable time and resources which would not need to be expended if a switch could be tested prior to installation.
These and other problems exist.